package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisData;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private CacheClient cacheClient;
    @Override
    public Result queryById(Long id) {

        //互斥锁解决缓存击穿
        //缓存击穿其实就是某个被高并发访问的key(也称为热点key),当key过期时，大量线程并发访问，此时会集中访问
        //数据库，从而导致效率低下
        //解决方法是使用互斥锁，key过期后的第一个访问拿到锁，去访问数据库并重建缓存，重建的过程中
        //其他访问来当发现key过期后也会尝试去访问数据库，此时就只能休眠并重新访问缓存，不会去访问数据库,
        //Shop shop = queryWithMutex(id);

        //解决缓存穿透
        /*Shop shop = cacheClient.queryWithPassThrough(CACHE_SHOP_KEY,id,Shop.class,id2->
            this.getById(id2)
        ,CACHE_SHOP_TTL,TimeUnit.MINUTES);*/

        //逻辑过期解决缓存击穿
        Shop shop = cacheClient.queryWithLogicalExpire(CACHE_SHOP_KEY, id, Shop.class, this::getById, CACHE_SHOP_TTL, TimeUnit.MINUTES);

        if(shop==null){
            return Result.fail("店铺不存在!");
        }
        return Result.ok(shop);
    }

    @Override
    @Transactional
    public Result update(Shop shop) {
        Long id = shop.getId();
        if (id==null) {
            return Result.fail("店铺id不能为空");
        }
        //1.更新数据库
        updateById(shop);
        //2.删除缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY + shop.getId());
        return Result.ok();
    }
}
